How to find Effective inductance for series/parallel mutually coupled coils

Discussion in 'Homework Help' started by nlr_1986, Aug 20, 2010.

  1. nlr_1986

    Thread Starter New Member

    Aug 20, 2010
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    Hi to all the members!
    i have been given one problem of finding effective induactance for the coils as drawn in figure between ab terminal.
    L1=L2=L3=2H and M=1,
    so, how i could get the solution.
     
  2. The Electrician

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    Oct 9, 2007
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    Your subject line mentions "mutually" coupled coils, but your schematic doesn't show any mutual coupling. Without knowing the mutual inductance, you can't calculate the answer.
     
  3. nlr_1986

    Thread Starter New Member

    Aug 20, 2010
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    I have indicated the dots in figure and mutual iductance M=1 for three coils
    and this example is given as unsolved to me and i want to get solution of it
     
  4. retched

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    Dec 5, 2009
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    Series inductance and parallel inductance?

    Do you want to know the inductance as measured at the dots?
     
  5. nlr_1986

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    Aug 20, 2010
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    i want effective inductance between terminal A&B.
     
  6. JoeJester

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  7. t_n_k

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    Mar 6, 2009
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    Has anyone got a solution for this one. I assumed the OP meant the mutual inductance from any one winding to another was the same value of 1H.

    After some laborious algebra I calculated Lab=11/6 H. Anyone concur?
     
  8. The Electrician

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    Yes, that's what I get also, but shouldn't we ask the OP to show some work before we give the answer?
     
  9. t_n_k

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    Sure - I agree. I'm guessing the OP's teacher wouldn't be satisfied with the just the unworked answer. From my experience as a student it was always frustrating not to have the 'correct' answer. At least you had a check of your worked result. But we haven't heard from the OP anyway, so I'm also guessing they have moved on.
     
  10. JoeJester

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    Unfortunately that happens, which is why the rules get mentioned so often.
     
  11. nlr_1986

    Thread Starter New Member

    Aug 20, 2010
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    ur answer is right but how u get it?
     
  12. nlr_1986

    Thread Starter New Member

    Aug 20, 2010
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    sorry for not replying in time
    i was applying KVL in circuit shown in figure.and try to get equation
    v=Leqdi/dt

    but i get answer by that is 1.25

    so plz tell me the procedure to get right answer that is 1.83H
     
  13. The Electrician

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    Oct 9, 2007
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    Do you know how to write the loop equations for a circuit? Did you try to do this for your problem?

    I'll have another look for your response in a few hours.

    If you will show the details of how you got 1.25, perhaps we could you find the error in your calculations.
     
    Last edited: Aug 30, 2010
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